Motorized snowboard

ABSTRACT

A gasoline engine powered snowboard having an endless track trained about a support frame containing driven and idler wheels. Engine operation is directed from an upright operator support column. A molded chassis is hinge coupled to pivot about alternative contoured track support pan assemblies. The pan support assemblies cooperate with flexible track surfaces (e.g. fringe or pleat members) and foot supports to enable steering with foot and body movements. A lower support pan exhibits convex edge surfaces that contact track pleats or fringe pieces and includes an elliptic longitudinal channel. Alternative upper support pans provide a reciprocating wheeled steering plate, longitudinal drive lug channels and contoured snow diversion surfaces and/or an agitator. Internal track surfaces include UHMW pieces at or aligned to the drive lugs. Ground contact lugs exhibit traction promoting and snow clearing contoured profiles, shapes and recesses.

RELATED APPLICATION DATA

This is a divisional application of Ser. No. 12/378,370 filed Feb. 13,2009, now U.S. Pat. No. 7,900,723, which is a continuation-in-part ofapplication Ser. No. 12/002,840, filed Dec. 19, 2007, now U.S. Pat. No.7,686,109, which is a continuation-in-part of application Ser. No.11/652,455 filed Jan. 11, 2007, now U.S. Pat. No. 7,784,571, andapplication Ser. No. 29/271,188 filed Jan. 11, 2007, now D567,712.

BACKGROUND OF THE INVENTION

The present invention relates to a powered snowboard assembly and, inparticular, to a gas engine powered snowboard having an endless trackwith flexible lateral, peripheral edges (e.g. slots or pleats) supportedto rotate about a frame assembly in contact with an interchangeablechassis support pan. A recess in the pan and associated flanges, rails,beveled surfaces and/or a wheeled slider assembly promote track flexionand steering in response to weight adjustments placed on foot controlsurfaces.

A wide variety of engine powered, personal transport vehicles have beendeveloped for recreational travel over land, water and snow. Some dryland skateboard type vehicles that accommodate a standing operator areshown at U.S. Pat. Nos. 6,435,290; 5,127,488; and 4,143,728. Some snowbased vehicles that accommodate seated operators are shown at U.S. Pat.Nos. 4,534,437 and 3,794,131. Several track supported snow vehicles thataccommodate standing operators are shown at U.S. Pat. Nos. 6,698,540;6,193,003; 5,662,186; 5,305,846; 4,984,648; and 4,307,788.

Different types of downhill snowboards and related improvements havealso been developed to satisfy the ever changing human desire forchallenging recreational devices. U.S. Pat. No. 5,662,186 is directed toa powered snowboard having multi-section operator and engine platformsthat align at different inclinations. The vehicle however is notparticularly adapted to mimic the operating experience of a conventionalun-powered snowboard.

The present invention was developed to provide a motorized snowboardwith the agility of a non-motorized snowboard. The device supports astanding operator and, except for engine operation, is controlled andsteered with foot movements that substantially mimic the experience ofriding a conventional snowboard. Use of the subject snowboard is howevernot limited to steep or hilly terrain. Instead, the snowboard can beused over moderate hills and undulating or flat terrains to provide anoperator a more athletic experience than merely riding a snowmobile. Thesnowboard is also configured to be user friendly to facilitate access tothe track with a hinged chassis assembly. Upper and lower track supportpans having judiciously arranged contour curvatures minimize snow andice build-up in the spaces between the track and chassis and between thetrack and support pans and optimize steering control.

SUMMARY OF THE INVENTION

It is a primary object of the invention to provide an engine poweredvehicle that can be steered with foot and/or body movements.

It is further object of the invention to provide an endless trackvehicle that can be operated by an upright operator over a variety ofsurfaces (e.g. snow, ice, hard pack, sand etc.).

It is further object of the invention to provide an endless trackvehicle having an upright hand hold, control column.

It is an object of the invention to provide a vehicle with a supportframe having a drive sprocket and a plurality of idler wheels thatcooperate with an engine to drive a flexible track mounted to asurrounding chassis.

It is further object of the invention to provide a vehicle with anoperator directed cable-type or electromechanical control linkage to theengine, control surfaces or other equipment assemblies.

It is further object of the invention to provide a track having aplurality of slits, pleats or other flexible or resilient surfaces thatdefine resilient track regions that flex, expand and/or contract toaccommodate body-shifting movements to steer the vehicle.

It is further object of the invention to provide a track havingtransverse fringe pieces that support flexible ground contacting lugs.

It is further object of the invention to provide a track having pleatsthat transversely extend from peripheral track edges to enable trackflexion and promote steering.

It is further object of the invention to provide a track having rows oftransversely extending lugs that depend from a central track portion andadjoining, laterally staggered, flexibly resilient track sectionscontaining steering lugs and wherein the flexible track sections flexand cooperate with contoured chassis support surfaces to promotesteering.

It is further object of the invention to provide ground contact steeringlugs at flexibly resilient track surfaces that exhibit raised isoscelestriangular-shaped surfaces and that transversely extend at obtuse anglesfrom interconnected lugs depending from the center portion of the track.

It is further object of the invention to provide a track havingstiffener and/or wear rods with formed sections contoured to the trackand molded into the track to reduce track friction at contact surfaceswith a track support assembly.

It is further object of the invention to provide a track having ultrahigh molecular weight (UHMW) stiffener rods or other performanceenhancing devices thermo formed to desired shapes and/or bonded to ormolded contemporaneously with the forming of steering lugs or othertrack surfaces.

It is further object of the invention to provide an interchangeable,contoured track support pan at the bottom of the chassis that cooperateswith drive and steering lugs and flexible track surfaces to steer thevehicle with operator foot and body movements.

It is further object of the invention to provide a track support panassembly with beveled track engaging surface(s), drive lug receivingrecess(es), rail(s) and/or other mechanisms to prevent trackdislodgement and promote flexion at adjoining flexible track steeringsurfaces.

It is further object of the invention to provide a track supportassembly including a lower pan with a beveled, inverted V-shapedreciprocating slide plate with domed track engaging wheels thatselectively direct and/or flex the track to promote steering.

It is further object of the invention to provide a track support panhaving a central, elongated, ovular recessed channel exhibitinglongitudinal and transverse concave curvatures and transverse convexcurvatures along longitudinal surfaces adjoining the channel.

It is further object of the invention to couple a reciprocating trackflexing assembly mounted to a support pan with spherical couplers toenhance reciprocating steering movements.

It is further object of the invention to provide a track having ultrahigh molecular weight (UHMW) caps, plugs or other slippery, wearresistant devices mounted and/or formed into the drive and/or steeringlugs.

It is further object of the invention to provide a track support with asnow and ice diverting assembly.

It is further object of the invention to provide snow relieving surfacesat the endless track that cooperate with a snow and ice diverter shieldor support pan.

It is further object of the invention to provide a plastic track supportor diverter pan exhibiting compound curvatures at fore and aft endcorners to minimize snow and ice build up between the track and supportpans.

It is further object of the invention to provide a track assembly withsnow and ice agitating and exhaust means to discharge ice and snow fromwithin the track assembly.

The foregoing objects, advantages and distinctions of the invention areobtained in alternative track frame assemblies having dedicated orinterchangeable track support pans. In one construction, the snowboardcomprises an endless track trained about a track support framecontaining driven and idler or “bogie” wheels. The track support frameis mounted to a molded chassis having forward and rear foot supports. Agasoline engine mounts to the chassis and a drive linkage couples theengine to the track support frame and depending endless track. Enginedrive power is transferred via a clutch and interconnected chain/beltdrive linkages to a drive shaft that supports a track drive sprocket andidler shafts that support drive wheels that engage an interior surfaceof the track.

Engine operation is directed from an operator's column and cablingand/or electro-mechanical servos coupled to the engine. The bottomsurface of the chassis provides a chassis or track support pan assemblythat in one version includes a longitudinal recess and contouredsurfaces that engage flexible portions of the track to directionallypromote track movements to steer the vehicle in response to weightshifting movements at the foot control surfaces.

Drive lugs project from the interior track surface, follow thelongitudinal recess and engage the drive and idler sprockets. Peripheraledge portions of the track follow shaped contours of the chassis supportpan. The support pan can exhibit bevels and/or valleys, recesses,cutouts and/or other surface shapes that flex the track to directionallypromote track movement or flexion in cooperative response to operator orother induced movements. Idler wheels depending from a chassis coverpiece follow one or more channels between ground engaging lugs andcontrol lateral movement of the track at the track support pan assembly.The support pan can also support and/or cooperate with assemblies thatselectively engage and/or direct flexible steering portions of thetrack.

The track is presently divided into a center portion containing uprightinterior drive lugs and flexible fringe or pleated portions. The centerportion exhibits a relatively narrow width (e.g. less than one-third theoverall track width) and from which the drive lugs project in rows andpass between opposed longitudinal arcuate sidewalls (e.g. ovular) of alongitudinal recess at the support pan. Lateral movement of the track islimited by contact between the drive lugs and the recessed side walls ofthe support pan. Adjoining surfaces of the flexible fringe or pleatedtrack portions contact beveled surfaces at the support pan to promotesteering.

The ground engaging lugs exhibit contoured thickness profiles and defineidler wheel channels. Depending forward and trailing surfaces taper to aridged apex. The lateral extension of the forward and trailing lug,surfaces define a straight central portion and end portions thatobtusely radiate relative to the central portion. Collectively, the lugsdirect forward track movement as rows of depending ground contactinglugs at filamentary fringe or pleated portions of the track flex withoperator movements as the fringe or pleated portions follow thecontoured support pan to directionally promote steering movements.

Ground contact surfaces of the flexible fringe or pleated track portionscontain rows of laterally depending steering lugs. The flexible trackportions are defined by seriatim, slots or gaps that form fringe piecesor seriatim flexible pleats defined at flexible track surfaces. Thefringe and flexible track surfaces support rows of ground engagingsteering lugs. The region of ground contact of the steering lugs of eachfringe or flexible track piece transversely overlaps the span ofsteering lugs depending from adjoining fringe pieces or between pleats.

An alternative vehicle assembly provides a track with flexible pleatslocated along peripheral track edges. The pleats cooperate with aninterchangeable chassis/track support pan that can contain areciprocating steering plate having a number of wheels that contact thedrive lugs to shift the pleats into contact with beveled surfaces at thesupport pan. The steering plate is supported from spherical couplers andmounted to accommodate reciprocating lateral movement. Formed axles atthe wheels permit independent tilting movement at the wheels to enhancecontrol over wheel-to-drive lug contact and track flexion.

UHMW plastic stiffener rods are molded into the track in parallelco-axial alignment with the steering lugs. The rods are fitted to thetrack during lay-up and bent during molding to align with desired tracksurfaces. In one track construction openings or pockets are formed intothe steering lugs as the rods are bent to shape. The rods are locatedand formed to reduce friction and improve the wear resistance of thetrack with support pan contact.

Other improvements include UHMW plastic caps and/or plugs or otherdevices that are molded or mounted into the track lugs to reducefriction with support pan contact and improve the wear resistance andsteering control of the track. Apertures are provided in the track torelieve and/or prevent collection of snow and ice in the chassis andenhance track flexion. A shield or snow diverter is provided to preventbuildup of snow and ice at the track flexion/steering wheels. Snow andice agitators and an exhaust assembly cooperate with the shield toremove snow from beneath the chassis and track assembly.

A further improved chassis and track support assembly is disclosed thatprovides a hinged support adapted to extend between right and left slidepan rails and a chassis to cover piece to permit a clam shell pivotingof the cover piece for inspection of the track and track support panassembly and/or vehicle maintenance. An improved lower track support panprovides a longitudinal, ovular track containment channel that exhibitslongitudinal and transverse concave contours relative to the ground.Longitudinal peripheral pan edges exhibit a convex transverse curvaturerelative to the ground. An upper plastic snow and ice diverter panexhibits compound curvatures at fore and aft end corner surfaces todirect and divert snow and ice rearward and outward from the spacebetween the upper pan and track.

Still other objects, advantages, distinctions, constructions andcombinations of individual features of the invention will become moreapparent from the following description with respect to the appendeddrawings. Similar components and assemblies are referred to in thevarious drawings with similar alphanumeric reference characters.

The description to each combination should therefore not be literallyconstrued in limitation of the invention. It is also to be appreciatedthe singular improvements can be combined in any variety of trackassemblies. The invention should therefore be interpreted within thebroad scope of the further appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view to a personal, engine powered snowboardassembly.

FIG. 2 shows a right side view of the snowboard assembly and wherein themounting relationship of the engine, clutch, and chain and belt trackdrive linkages are more apparent.

FIG. 3 shows a longitudinal cross section view to the track supportframe, drive and idler sprockets.

FIG. 4 shows a perspective view to the mounting relation of the track tothe bottom track support pan and ground engaging surfaces of thesnowboard assembly.

FIG. 5 shows a perspective view to the right side and bottom controlsurface of the snowboard assembly with the drive linkage cowling andtrack removed.

FIG. 6 shows a plan view of the ground engaging, exterior surface of thetrack depicting the arrangement of the displaced, transverse, laterallyextending steering lugs.

FIG. 7 shows a transverse cross section view through the track takenalong reference lines 7-7 of FIG. 6.

FIG. 8 shows a transverse cross section view through the track takenalong reference lines 8-8 of FIG. 6.

FIG. 9 shows a diagrammatic plan view of a portion of the track in anun-flexed, straight line condition and wherein alternative operatordirected, wheeled steering assemblies (shown in dashed line) are mountedto mechanically flex the track.

FIG. 10 shows an end view of the track centered along the chassissupport pan in an un-flexed, straight line condition.

FIG. 11 shows a diagrammatic view of the interior surface of the trackin a flexed, turning condition.

FIG. 12 shows an end view of the track laterally shifted relative to thechassis support pan corresponding to the flexed, turning condition ofFIG. 11 and wherein operator directed steering members of thealternative assemblies of FIG. 9 are shown in dashed line.

FIG. 13 shows a top plan view to an interchangeable chassis mountedtrack support pan having a wheeled slide assembly that mechanicallyflexes the track.

FIG. 14 shows a bottom plan view to the interchangeable track supportpan assembly of FIG. 13.

FIG. 15 shows a side plan view to the interchangeable track support panassembly of FIG. 13.

FIG. 16 shows a front plan view to the interchangeable track support panassembly of FIG. 13.

FIG. 17 shows a cross section view to the slide assembly taken alongsection lines 17-17 of FIG. 13.

FIG. 18 shows a cross section view to the slide assembly taken alongsection lines 18-18 of FIG. 13.

FIG. 19 shows a cross section view to the slide assembly taken alongsection lines 19-19 of FIG. 13.

FIG. 20 is a perspective drawing top and side views to a section of apleated, flexible track.

FIG. 21 shows a top plan view to the pleated track section of FIG. 20.

FIG. 22 shows an end view to the pleated track section of FIG. 20 takenforward of the steering lugs.

FIG. 23 shows a side plan view to the pleated track section of FIG. 20.

FIG. 24 shows a bottom plan view to the pleated track section of FIG.20.

FIG. 25 shows a cross section view to the pleated track taken throughthe steering lugs and along section lines 25-25 of FIG. 21 and whereinthe drive lugs contain UHMW caps.

FIG. 26 shows a cross section view similar to the FIG. 25 and whereinthe drive lugs contain UHMW plugs molded into the drive lugs.

FIG. 27 shows a section view taken from the area of the encircledsection line F27 of FIG. 1 to a multi-vane snow and ice agitatorassembly mounted to the track guide wheels and cooperating with anadjoining exhaust chute.

FIG. 28 shows a perspective view to the top front and left side of animproved personal, engine powered snowboard assembly wherein the chassiscover piece is hinged open to expose the track support/slide panassembly.

FIG. 29 shows a perspective view to the bottom, left side and rearportions of the snowboard assembly of FIG. 28 and wherein the chassiscover piece is hinged open and the bottom surface of the lower tracksupport pan is exposed.

FIG. 30 shows a perspective view to the upper, plastic track support panor diverter and the compound curvatures formed into the right and leftcorners at the fore and aft ends.

FIG. 31 shows a longitudinal, left side view of the upper, plastic tracksupport pan.

FIG. 32 shows a front view of the upper, plastic track support pan.

FIG. 33 shows a rear view of the upper, plastic track support pan.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With attention to the perspective view of FIG. 1, an improved snowboardassembly 2 of the invention is shown. The assembly 2 provides aframework or chassis 4 that is formed to support an upright operator.Fore and aft operator or steering platforms 6 and 8 are shaped andoriented to comfortably support an operator's booted feet. The exposedsurface of each of the two platforms 6 and 8 is constructed to providetraction to facilitate operator steering movements. The platforms 6 and8 can include surface knurling, granular coatings, fastened matting orother traction enhancing materials 10 that assure non-slippery contactwith the platform surfaces during normal use. Straps, bindings orsurfaces shaped to mate with an operator's foot ware (not shown) canalso be provided at the platforms 6 and 8.

Each platform 6 and 8 is shaped and sized to accommodate independentmovement of the operator's feet within the space and/or shifting of theoperator's weight laterally and/or fore and aft. The shifting of theoperator's weight particularly induces a supported drive track 12 shownat FIGS. 2-4 and 6-12 to flex and dynamically vary the contact of thetrack 12 with a bottom surface of a support pan 14 of the chassis 4 andground engaging lugs at the track 12 with the snow. The support pan 14is mounted between longitudinal flanges 63 and 65 of the chassis 4.Steering is thus obtained with the dynamic changes in track contact withthe supporting snow or ice.

Steering control is particularly obtained by constructing the supportpan 14 to include elongated contoured edge surfaces 66 and 68 (e.g.beveled) that bound a longitudinal recess 18. The recess 18 can forexample exhibit ellipsoid, ovular or other longitudinal arcuate-shapedside walls 19. The surfaces 66 and 68 and recess 18 are aligned tocooperate with interior surfaces of the track 12 to direct track flexionand retain the track to the chassis 4 over a range of steering motions.Simultaneous variations in vehicle speed can be applied to modulatesteering motions. Particular details to the construction of thecontoured edge surfaces 66 and 68 and recess 18 and responsive flexionof the track 12 are discussed below with respect to FIGS. 7 through 10.One or more rails might also be provided alone or in combination withthe recess 18 to limit lateral track movement and facilitate trackretention.

A gasoline engine 20 (e.g. 5-10 hp) is mounted between the footplatforms 6 and 8. The engine 20 is located relative to the platforms 6and 8 to slightly overweight the vehicle's aft end to maintain an upwardtrim angle at the fore end. The risks of possible operator dischargefrom the vehicle 2 due to porpoising or nose-diving with a downward trimangle are thereby alleviated. A DC motor with a storage battery or otherelectrically powered motor or hybrid power source (e.g. gas andelectric) with appropriate controls might alternatively be incorporatedinto the vehicle 2 in lieu of the gas engine 20.

A mechanical (e.g. cable) or electro-mechanical control linkage 22extends from the engine 20 and is manipulated by the operator. Thelinkage 22 is routed along an upright support column 24 or can be heldin an operator's hands. A cowling 23 that covers hand controls 26coupled to a cable 22 and fitted to the support column 24 is presentlypreferred. The column 24 also provides a degree of stabilization to theoperator during steering motions. The shape of the column 24 (e.g. tiltangle, bends, supports etc.) and coupling to the chassis 4 can beadjusted as desired to accommodate operator ergonomics and stabilize theoperator.

The shape of the column 24 (e.g. tilt angle, bends, supports etc.) andcoupling to the chassis 4 can be adjusted as desired to accommodateoperator ergonomics and stabilize the operator. Presently, the column 24is fastened to the chassis 4 and several alternative mounting holes areprovided to permit a 15° range of tilt adjustment. The column 24 is alsoconstructed in sections that interlock and telescope relative to oneanother. The adjustments collectively allow the user to establish adesired operating column height and pitch angle.

Although a cable 22 is presently used, a wireless, radio frequency (RF)electro-mechanical drive might also be adapted to the engine 20. In sucha circumstance, an operator handheld controller 27 (shown in dashedline) might transmit RF signals via provided actuators (e.g. button,slide or joy stick) and a transceiver to one or more electro-mechanicalservos (e.g. relays, solenoids, pistons) responsively coupled to thevehicle 2 (e.g. engine throttle). Engine operation and other operatingmechanisms and parameters might thereby be controlled. Other servosmight be mounted to the chassis 4, for example, to vary the shape of thesupport pan 14, change the ground contact surface of the chassis 4 ordirectly interact with flexible steering surfaces to direct trackflexion.

In the latter regard, one or more flexing members, slide pads orroller(s) 29′ (shown in dashed line at FIGS. 3 and 10 can be mounted tothe chassis 4 to bear on an appropriate interior surface(s) of the track12 to flex the track 12 and induce a desired steering. The rollers 29′can exhibit different shapes (e.g. circular, elliptical) or be mountedfor eccentric rotation from a supporting assembly to provide adifferential contact with the track 12. The rollers 29′ might also bemounted to a support frame that actively or passively moves relative tothe support pan 14 to appropriately flex filamentary members at thetrack 12. Control of the rollers 29′ might also be actively directedwith linkages that direct the rollers 29′ to contact the track 12 withvarying degrees of force at preferred track surface locations (e.g.bordered within the track or along peripheral edges) as appropriate.Details to the construction of the track 12 and cooperation with thechassis 4 to effect steering are provided below.

The engine 20 is encased beneath a cover or safety shroud 28 to preventoperator contact with any moving parts or the exhaust system. The engine20 is mounted to direct exhaust gases away from the operator. A hingedshroud 31 is mounted to the side of the shroud 28 and covers a clutchand drive linkage assembly 30 coupled to the track 12. The chassis 4 caninclude other safety features and can be formed to exhibit any desiredaerodynamic and/or aesthetic shape. The chassis 4 might also beconstructed to accommodate multiple operators, passengers or permittowing of sleds or accessory appliances.

With attention to FIGS. 2 through 5, views are shown to the drivelinkage 30. The linkage 30 includes a centrifugal clutch 32 that ismounted to an output shaft 33 of the engine 20. A drive belt 34 extendsfrom the clutch 32 and is trained around another centrifugal clutch 36supported to a transfer shaft 38. A belt 40 is trained from anothersprocket (not shown) mounted beneath the clutch 36 to a sprocket 44fitted to an idler shaft 46. Yet another belt 48 extends to a trackdrive shaft 50 and sprocket 52 mounted to the shaft 50.

A track drive sprocket 54 is centered on the shaft 50 and providesseveral lateral extending teeth 56 that engage upright drive lugs 58that project from an interior surface of the track 12. Multiple drivesprockets 54 can also be fitted to the chassis 4. Exposed ground lugs 59depend from the exterior surface of the track 12 and engage the snow.The ground lugs 59 are constructed and positioned to direct forwardmotion and facilitate steering.

Separately depicted at FIG. 3 is a diagrammatic view to the routing ofthe track 12 relative to the chassis 4. The interior surface of thetrack 12 is trained around the aft drive sprocket 54 and a pair offorward idler wheels 60 mounted to an idler shaft 61. The chassissupport pan 14 supports the bottom of the track 12 intermediate the aftsprocket 54 and front wheel(s) 60. Several rubber coated idler wheels 51and 53 ride on the upper surface of the track 12. The idler wheels 51and 53 are mounted to intermediate idler shafts 55 and 57 fitted to thechassis 4. The idler wheels 51 and 53 support the track 12 to direct thetrack in non-contacting relation beneath the foot support platforms 6and 8 and engine 20. The idler wheels 51, 53 and 60 are mounted to beadjustable and/or resiliently biased to maintain a relatively constanttension on the track 12. The wheels 60 can also support agitatorsdiscussed below at FIG. 27 to pulverize and exhaust collected snow andice and improve track control and vehicle performance.

With additional attention to FIG. 5, the track 12 otherwise contacts androtates over the contoured, longitudinal slide surface of the chassis ortrack support pan 14. Exposed longitudinal flanges 63 and 65 of thechassis 4 extend along the sides of the support pan 14 and glide overthe snow. Adjacent the flanges 63 and 65 are the contoured surfaces 66and 68 of the support pan 14 that exhibit a slight inverted V-shapedbevel when viewed end-on relative to the ground, reference FIGS. 10 and12. The drive lug recess 18 extends the length of the support pan 14 andis centered between the track contact surfaces 66 and 68. The drive lugs58 rotate in and are contained by the recess 18. More details to thecooperation of the track 12 with the beveled surfaces 66 and 68 toachieve steering are discussed below with respect to FIGS. 9 through 12.

Mounted to the chassis 4 to engage opposite ends of the forward idleraxle 61 are adjustable tensioners 72. The tensioners 72 are supported todirect the shaft 61 in a differential eccentric fashion. Upon rotatingthe tensioners 72 relative on the shaft 61, eccentric surfaces or aneccentric action of the tensioners 72 direct the idler wheels 60 fore oraft to vary the tension of the track 12. The tension is normally set tocenter the rotation of the track 12 relative to the idler wheels 60 andsupport pan 14.

The novel construction of the track 12 is particularly depicted at thepartial plan and cross section views of FIGS. 6-8. The cooperation offlexible track surfaces with the support pan 14 provide steering controland maneuverability over the snowboard 2 and the details of which areshown and discussed with respect to FIGS. 9-12.

Returning attention to FIG. 6 however and in distinction to acontinuous, constant width belt, the belting of the track 12 isconstructed with a number of lateral notches, gaps or slots 76 that areformed into left and right fringe portions 77′ and 77″ of the track 12.The slots 76 extend from a center drive portion of drive band 78 to leftand right peripheral edges of the track 4. The slots 76 define flexibletrack pieces or filamentary fringe pieces 80 at the fringe portions 77′and 77′ radiate from the central drive band 78 relative to alongitudinal center axis “A” along transverse axes “B”. Smooth interiorsurfaces 82 of the fringe pieces 80 engage the beveled edge surfaces 66and 68 of the support pan 14. Although the slots 76 are shown openended, the slots 76 may be closed ended; that is, the filamentarymembers 80 may be bordered or circumscribed by surrounding portions ofthe track 12

A series of laterally displaced drive lugs 58 project from the interiorsurface of the drive band 78 and engage the sprocket teeth 56 and passalong the central portion of the pan 14 and the recess 18, referenceFIGS. 7 and 8. Rows of the ground engaging ground lugs 59 depend fromthe opposite, exterior side of the drive band 78 and the fringe pieces80. The ground lugs 59 are shaped and arranged to optimize forwardtravel.

The ground lugs 59 are organized into alternating rows 82 and 84 of lugs86 and 92 that exhibit shapes designed to optimize vehicle performanceover snow. The rows 82 each provide a single lug 86 that approximatelyspans the width of the central band 78. The lugs 86 depend from thetrack 12 between the overlying drive lugs 58. Each lug 86 provides anupright center piece 88 having a center recess 89. End pieces 90 extendat obtuse angles from opposite ends of the center piece 88. Leading andlagging surfaces (relative to the track travel direction) of the lugpieces 88 project from a relatively wide base at the track surface to anarrow elevated apex 91. The lugs 86 thereby exhibit an elongated,inverted V-shape relative to the rotational travel direction of thetrack 12.

The alternating rows 84 separately provide lugs 92 that span both thecenter drive band 78 and the fringe pieces 80. The rows 84 extendbeneath the drive lugs 58. Each lug 92 is constructed of a trapezoid orpyramidal-shaped center piece 94 and laterally displaced end pieces 96.The center and end pieces 94 and 96 are coupled together with straight,upright web pieces 98.

The end pieces 96 extend the width of the fringe pieces 80 at the rows84. The end pieces 96 include short horizontal sections 100 and longerend steering sections 102 that extend at obtuse angles from thehorizontal sections 100. The lug and web pieces 96 and 98 project from arelatively wide base at the track surface to a narrow apex 104. Thecenter piece 94 rises to an apex 106 approximately twice the width ofthe apex 104.

The lugs 92 also exhibit an elongated, beveled V-shape relative to theground and rotational travel direction of the track 12. Rotation of thecenter pieces 94 overlaps the regions of ground contact of the lugs 86and movement of the fringe pieces 80 and particularly the end sections102 provides steering control.

In the latter regard and with attention to FIGS. 9 through 12, vehiclesteering is achieved by dynamically varying the contact of the smoothinterior surfaces 82 of the fringe pieces 80 with the beveled supportpan surfaces 66 and 68. FIGS. 9 and 10 depict a straight line conditionwherein the operator's weight is centered on the chassis 4 with thesupport pan 14 generally riding horizontal to the ground. The fringepieces 80 shown without the steering lugs 102 are correspondinglycentered over the support pan 14.

Steering is achieved by varying the operator's position and/or weight onthe operator platforms 6 and 8 to change the contact dynamics of thetrack 12 with the support pan 14. For example, as the operator appliesweight to the left side of the chassis 4 and with attention to FIGS. 11and 12, the support pan 14 tilts. The left side of the track 12 engagesthe snow, the fringe pieces 80 at the left fringe portion 77′ collapseor compress inward against themselves as they contact the beveled edgesurface 66 of the pan 14. The compression of the left side of the track12 causes the left side to cup which action exaggerates the grippingaction of the left side lug end sections 102 with the snow. The drivelugs 58 correspondingly move to the right in the recess 18 and contactthe sidewalls of the recess 18.

The respective slots 76 and fringe pieces 80 at the right fringe portion77″ independently diverge and the interior surface 82 at the right sideof the track 4 rotates with limited contact with the beveled surface 68.The vehicle 2 responds to the opposing compression and expansion of thefringe pieces 80 at the slots 76 to turn left or right. The simultaneousgripping of the snow by the end pieces 96 of the drive lugs 58 enhancesthe responsiveness of the vehicle 2 to turn.

In a similar fashion, the controlled application of force on the fringepieces 80 via the steering rollers 29′ shown in dashed line at FIGS. 9and 12 can produce directional steering flexion. The flexion can bederived by depressing one side of the rollers 29′ and/or elevating theother side relative to the fringe members 80. The axles 25 can bemanipulated in different fashions similar to shifting an operator'sweight to derive appropriate track contact. Additional steering rollers29″ shown in dashed line at FIG. 3 can also be mounted at the ends ofthe recess 18 to re-center the track 12 relative to the drive sprocket54 and/or idler rollers 60.

Also shown at FIG. 9 in dashed line is a sliding assembly whereinsteering rollers 29′ and axles 25 are mounted to “L” brackets 110 thatspan a cutout region 112 in the pan 14. The brackets 110 permit therollers 29′ to laterally slide to and fro to engage the fringe members80. Contact of the drive lugs 58 with the side walls 19 of the recess 18or other pan surfaces limit lateral track movement. Stops (not shown)may also be fitted to the pan 14 to engage the brackets 110. Thebrackets 110, rollers 29′ and/or axles 25 can be mounted for operatordirected movement or externally directed movement with an appropriateexternally operated actuator and linkage.

An alternative, presently preferred chassis pan/slide roller assembly200 is shown in detail at FIGS. 13 through 19. The assembly 200 can beinterchangeably mounted to the chassis 4 in lieu of the chassis supportpan 14. The assembly 200 is used with a further improved track 230having pleats 202 formed into the track 12 in lieu of slits 76. Theassembly 200 can also be used with a track 12 having fringe members 80in the fashion of the brackets 110 and rollers 29′. Views to theimproved track 230 are depicted at FIGS. 20 through 26.

The assembly 200 provides a bent, elongated pan or plate 204 thatsubstantially covers the bottom of the chassis 4 in the space betweenthe drive sprocket 54 and idler wheels 60 and exhibits a concave orbeveled, inverted V-shape relative to the ground when viewed end on,reference FIGS. 16-19. The plate 204 mounts to the chassis 4 in lieu ofthe chassis support pan 14. The assembly 200 serves the same generalfunction as the chassis support pan 14, recess 8 and beveled edges 66and 68.

Fore and aft guide wheel assemblies 206 and 208 are supported to theends of the plate 204 as shown in FIGS. 13 through 17. The guide wheelassemblies 206 and 208 each provide a pair of domed plastic and/orrubber coated wheels 210. The wheels 210 are supported from a straightaxle 212 that extends between right and left axle brackets 214. Thebrackets 214 are fastened to the plate 204 at openings 215. The wheels210 contact the interior surface of the track 4 and align with the sidesof the drive lugs 242 as the lugs 242 pass over the ends of the pan 204to maintain the track alignment and prevent disengagement of the track230 from the chassis 4.

Mounted between the center guide wheel assemblies 206 and 208approximately midway along the plate 204 and shown in detail at FIGS.13, 14 and 17-19 is a track steering assembly 220. The steering assembly220 supports three paired sets of track flexion wheels 222. Each pair ofwheels 222 is supported to a bent, inverted V-shaped axle 224, referenceFIG. 19, that extends between right and left axle brackets 226. Thesteering assembly operates in the longitudinal space between the guidewheels 210.

The axles 224 are formed to align the wheels 222 relative to thebrackets 226 and plate 204 to contact the drive lugs 242 and laterallydirect the pleats 202 formed into the peripheral edges of the track 230.The axles 224 align the wheels 222 slightly offset (e.g. in a range of15° to 25°) from being orthogonal to the plate 204. The domed or arcuatesides of the wheels 222 thereby maintain efficient contact with thetrack 230 and lugs 242 as they ride over the track 230. The ends of theaxles 224 are secured to the brackets 226 with couplers 228 that containspherical bearings 229. The couplers 228 and bearings 229 permit theaxles 224 and wheels 222 to float or wobble as they contact the track230.

Although a particular axle 224 and coupler 228 have been shown, axles224 of other shapes and cooperating with other couplers or connectinglinkages can be used to obtain other floating assemblies with multipleaxes of movement at the wheels 222.

The axle brackets 226 are retained to the lateral sides of a centeraperture 232 formed into the plate 204. The brackets 226 are mounted ina fashion that permits a side-to-side reciprocating movement of thebrackets 226. The movement is achieved with a retainer plate 234, highdensity slide bearings 235 (e.g. UHMW plastic) and bushings or spacers236 that surround fasteners 237 used to capture the brackets 226, plates234 and bearings 235 to slots 239 formed into the plate 204 adjacent theends of the aperture 232.

The bearings 235 and bushings 236 permit the brackets 226 and wheels 222to freely slide to and fro relative to the aperture 232 independent ofthe freedom of movement of the brackets 226 and the spherical couplers228. The wheels 222 are thus able to slide along the pan 204 and tilt orwobble and move laterally to accommodate operator steering motions. Thecombination mounting of the wheels 222 provides a firm grip of the track230 and drive lugs 242, yet permits the wheels 222 to tilt and move asthey encounter the lugs 242 and laterally direct the pleats 202 over thebeveled surfaces of the pan 204 to flex and flatten the pleats 202. Asone side of the pleats 202 flatten and expand with increased groundcontact, the opposite side pleats relax and contract. The changingcontour of the track 230 thus responds in a similar fashion to thefringed track 12 as shown at FIGS. 10 through 12 and varies the track'sgrip with the snow to steer the vehicle.

FIGS. 15 and 16 further depict a plate or tray 225 (shown in dashedline) that can be fitted to the chassis 4 to prevent and/or minimize thecollection of snow and ice between the chassis 4 and the support pan204. The tray 225 particularly fastens to the support plate 204 and ispositioned to direct snow that enters the apertures 215 and/or 232forward with movement of the drive lugs 242 and raised slide surfaces250 that are described in detail below. The surfaces 250 contain thermoformed UHMW track stiffener members 246 that are located and exposed atthe interior surface of the track 230 to reduce the friction between thetrack 230 and the support pan 204.

Details to the particular construction of the improved track 230 areshown at FIGS. 20 through 25 wherein respective perspective, top, sideand end views of the track 230 are shown. FIG. 20 depicts a sectionalperspective view of the interior surface of the track 12 and severalseriatim pleats 202 and adjacent surfaces 231. Each pleat 202 rises andextends to an adjoining peripheral track edge at an acute angle in therange of 5 to 20 degrees and projects approximately ½ to 1 inch from thebottom of the track 230 at its maximum height. The wall thickness (e.g.⅛ to 3/16 inch) and construction of each pleat 202 is sized and formedto promote flexion as the wheels 222 contact the lugs 242 and direct thetrack 230 left and right. The pleats 202, in turn, expand and contractas they move over the beveled or ramped surfaces of the support pan 204.As the wheels 222 move laterally and run against the drive lugs 242, thepleats 202 engage the beveled surfaces of the support pan 204, flattenand expand or relax and contract in relation to the degree of contactwith the support pan 204.

Each pleat 202 rises to a ridged apex 201 or hinge where each pleat 202expands and contracts as the wheels 222 slide laterally and direct thepleats 202 relative to the contours of the support pan 204 to flex andexpand or relax and contract. Relief channels 233 are formed into theinterconnecting junctions of the sidewall webs of each pleat 202 withthe bottom surface of the track 12 to similarly promote flexion of thepleats 202. Flexion of the pleats 202 can also be enhanced by providingapertures or recesses 251 (shown in dashed line) in the track 230 at theapex of the V of each pleat 202. The size and shape of the apertures 251can be established as desired. The apertures 251 also exhaust snow fromthe interior of the track 230 that collects above the tray 225. Theforegoing details can be seen along with the relative locations of thepleats 202, ground gripping lugs 238 and 240, and drive lugs 242 andrelated improvements thereto at FIGS. 21 through 26

Although V-shaped pleats 202 are shown, other raised or flexible shapedtrack surfaces can be incorporated into the track 230. The pleats 202 orother flexible members can be transversely aligned to extend at anydesired angular orientation to a longitudinal center axis of the track230, although presently extend at an acute angle or orthogonal to thelongitudinal track axis. The flexible surfaces can be located along theperipheral edges or can be located so they are circumscribed byadjoining portions of the track to cooperate with mating chassissurfaces or assemblies supported to the chassis 4. The flexible surfacesdesirably should direct the flexible portions of the track 230 to expandand contract at opposing regions to promote steering changes.

With attention to FIGS. 24 through 26 additional details are shown toimprovements to the lugs of the track 230. Projecting from the bottom,ground engaging surface of the track 230 and coaxially aligned with thepleats 202 are a series of centered, ground gripping lugs 238.Longitudinally offset from the lugs 238 and depending opposite theraised surfaces 250 are elongated steering lugs 240 that span the widthof the track 230. The lugs 240 include recessed cavities 248 designedand located to enhance the gripping characteristics of the track 230.The shapes and locations of the cavities 248 can be varied as desired.The present cavities 248 overly the raised surfaces 250 at the trackinterior and the thermo formed track stiffeners 246 that are molded intothe track 230.

As the cavities 248 are formed in a track mold, UHMW stiffener members246 previously supported in the mold and/or to the track blank arecontemporaneously bonded to the track 12 and formed to a shape toenhance track cooperation with the support pan 204. The members 246 areparticularly mounted to a partially formed track blank that is wrappedand wound with suitable belting, cording etc. The stiffener members 246are located to align with cavities in a track mold and presently spanthe track blank to collinearly align the stiffener members 246 to theultimately formed steering lugs 240. With several iterative engagementsof the mold at a suitable pressure and temperature, the rubber and UHMWmaterial at the track blank flow and/or bend to mold the track 230 tothe depicted shape.

The drive lugs 242 are coaxially aligned with raised surfaces 250 andstiffeners 246 that engage the support pan 204. The raised surfaces 250are described in detail below but contain thermo formed UHMW trackstiffener members 246 that are located to reduce the friction betweenthe track 230 and the support pan 204.

As the track blank is molded, portions of the mold are depressed intothe steering lugs 240 to form the cavities 248 in the ends of the lugs240. The heated stiffener members 246 are contemporaneously depressedand bent to define raised surfaces 250. The depressed cavities 248 thusimprove traction at the exterior ground gripping track surface andreduce friction at interior raised surfaces 250 which slide over thesupport pan 204 with reduced friction. The track wear and durability isthereby improved.

During construction of the track 230, caps 244 constructed of UHMWplastic or other high density material exhibiting relatively lowfriction relative to the support pan 204 can be positioned in the moldto align with the portions molded to define the drive lugs 242. The caps244 can also be separately fastened or bonded to the lugs 242 aftermolding, before or after the track 230 has cooled. As the track materialflows, the raised drive lugs 242 are formed and the caps 244 arethermally bonded to the drive lugs 242. Alternatively, the caps 230 and244 can be pressed or threaded into reduced size cavities. The cappeddrive lugs 242 provide enhanced track durability and reduced frictionand wear with the sprocket 54 and between the track 230 and support pan204. Alternatively, UHMW plugs 245 shown at 26 can be bonded, thermoformed or fitted to the lugs 242 during or after the molding of thetrack 230.

FIGS. 15 and 16 also depict an upper track support pan or snowdeflection or diverter pan 225 that can be made of metal or plastic thatcooperates with the track support pan 204 to control or minimize thecollection of snow and/or ice between the interior surface of the track12 and the upper pan 225 and in the spaces surrounding the apertures 215and 232. Any snow entering the apertures 215 and 232 collects above thepan 225 and is directed forward from an elevated aft flange 227 due tothe rotating action of the drive lugs 242 and raised surfaces 250 alongthe pan 225. The snow is directed to a discharge or exhaust port 260shown at FIG. 27 where the snow is ejected. The snow is also ejectedthrough the apertures 251 in the track 230. The reduction in snow andice buildup is also discussed below with respect to an improved upper,molded plastic diverter or track support pan 280 shown at FIGS. 30 to 33below

FIG. 27 depicts a section view to a further improvement to the chassisassembly 4 taken at the encircled section line F27 of FIG. 1. A snow andice agitator assembly 262 is particularly shown that mounts either tothe idler wheels 60 or adjacent to the wheels 60 along the idler axle61. Agitator vanes 264 are mounted to rotate and contact snow inside thechassis 4 or that is diverted via the shield 225 to beat and break upany ice particles. The pulverized material is directed to the exhaustchute 260.

Presently, several vanes or agitators 264 are mounted to the rims of theidler wheels 60. The vanes 264 are located and shaped to breakup ice andcrusted snow and direct the debris into the discharge port or exhaustchute 260 and away from the chassis 4. The exhaust chute 260 is sizedand shaped to prevent clogging and direct the debris away and withouthindering operation of the snowboard 2.

Although one construction and mounting of an agitator assembly 262 isshown, the agitators 264 can be constructed to different shapes and/orbe located elsewhere relative to the support pan 204 and track 230 topromote steering (e.g. the drive sprocket 54). The agitators 264 canalso include apertures at the vanes 264 and/or the edges can be shapeddifferently and/or include other surface shapes conducive to optimizingthe breakup of encountered chunks of crusted snow and ice before thepulverized debris is exhausted.

FIGS. 28 through 33 disclose additional improvements to the snowboard 2.FIGS. 28 and 29 particularly depict a snowboard 280 with a hingedchassis cover piece 282. The chassis cover piece 282 is coupled to atrack support pan assembly 284 at right and left forward, locking hingearms 286 and right and left rear pivot fasteners 288. The hinge arms 286permit the chassis cover piece 282 to be selectively elevated to accessthe track 12 (not shown) and to remove any ice and snow that mightcollect in the space between the cover piece 282 and track 12. The hingearms 286 include an over-center latching action that a lock when thecover 282 is sufficiently elevated. The arms 286 are released uponraising the cover 282 and folding the hinges 286 forward to permit thecover 282 to be fully lowered. A variety of other hinge assemblies canbe used to advantageously expose the track 12 and track support panassembly 284 to cleaning and maintenance.

Longitudinal rails 290 and 292 extend along the sides of the tracksupport assembly 284 and provide bent latch pieces 294 that projectthrough the cover piece 282. Lynch pins or other suitable fasteners (nowshown) mount to apertures at the latch pieces 294 to contain the chassiscover 282 during normal use.

Fitted between the side rails 290 and 292 are a refined upper diverterpan 295 and an improved lower track support pan 296. The lower supportpan 296 is formed to provide a longitudinal, concave ovular channel 298.The channel 298 is formed to exhibit compound longitudinal andtransverse concave curvatures relative the ground. Adjoining peripheralpan edge surfaces 300 and 302 exhibit convex bevels relative to theground such that the edge surfaces 300 and 302 rise from the channel asthey extend to the rails 290 and 292. The upper diverter pand 295 mountsover the lower pand 296 and fasteners 304 secure the rails 290 and 292to the overlapping upper pans 295 and 296. The compound convex andconcave curvatures of the lower support pan 296 facilitate vehiclesteering as the pleats 202 engage the perimeter pan edges 300 and 302and the channel 298 contains the drive lugs 242.

FIGS. 30 through 33 depict the improved plastic diverter pan 295. Thepan 295 is molded from plastic and includes a number of interconnectedcenter truss pieces 306 and end truss pieces 308. The truss pieces 306and 308 span between the side and end walls of the pan 280 to stabilizethe pan 295 against the normal movement of the track 12 over the pan295. Longitudinal channels 310 contain the drive lugs 242. The plasticmaterial is selected to accommodate the normal stress forces, operatingtemperatures and exhibit a slippery surface to the lugs 242, snow andice.

As discussed above, movement of the track 12 over the upper surface ofthe pan 280 desirably directs snow and ice outward and away from the pan295. The aft end 311 is elevated to deflect snow from the track 12 asthe track 12 rotates forward. The fore end 312 is lowered to deflectsnow from the track 12 as the track 12 rotates over the forward end. Theupper surface of the pan 295 and particularly the end corner surfaces314 and 316 exhibit diagonal, compound upward tapers to prevent thebuildup of ice and to direct snow and ice outward and away from thespace between the pan assembly 284 and the overlying track 12. Althoughone construction of the upper pan 295 is shown, the pan 295 can beconstructed from a variety of materials and exhibit a variety of shapesand structural supports. The upper surface contours can also be modifiedto further enhance the self-clearing of snow and ice the normal trackrotation.

While the invention has been described with respect to a presentlypreferred assembly and considered improvements, modifications and/oralternatives thereto, still other assemblies and arrangements may besuggested to those skilled in the art. It is also to be appreciated thatthe features of the foregoing chassis, frame and track can be arrangedin different combinations. For example, the track might be included witha different chassis configuration; the bottom contour of the support panmay be configured differently; a different track drive assembly may becoupled to the track; and/or the drive and/or ground contact lugs at thetrack and/or the slots between flexible filamentary members or thepleats can be configured differently. The diverter pan and/or theagitator can also be used with other snow vehicles or provided indifferent snowboard combinations. The foregoing description shouldtherefore be construed to include all those embodiments within thespirit and scope of the following claims.

1-17. (canceled)
 18. A motorized vehicle comprising: a) a chassissupporting an engine and an endless track and having an operatorplatform and wherein a bottom surface of said chassis includes acontoured longitudinal pan; b) a framework mounted to said chassisincluding a drive sprocket coupled to said engine and a plurality ofidler wheels, wherein said track is trained around said sprocket andidler wheels; and c) wherein said endless track includes a longitudinalcenter portion and adjoining first and second pleated portions, whereinsaid first and second pleated portions respectively comprise a pluralityof pleats that transversely extend and rise from opposed lateral sidesof said center portion toward longitudinal peripheral edges of saidtrack, wherein drive lugs project from an interior surface of saidcenter portion to engage said drive sprocket, wherein a plurality ofground engaging lugs transversely span and depend from external surfacesof said track, and wherein said pleats are mounted to contact saidlongitudinal pan and flex to vary the track contour under pressureinduced on said pan and pleats with operator movement and thereby steerthe vehicle.
 19. A vehicle as set forth in claim 18 wherein said pleatsextend toward said peripheral edges opposite each other and orthogonalto a longitudinal center axis of said track.
 20. A vehicle as set forthin claim 18 wherein said pleats comprise compound raised V-shaped ridgesthat transversely extend from an apex at said center portion andprogressively and laterally expand as they extend to the peripheraledges of said track.
 21. A vehicle as set forth in claim 18 wherein saidlongitudinal pan includes a longitudinal recess intermediate first andsecond beveled longitudinal surfaces and wherein said drive lugs arerestrained to pass along said recess.
 22. A motorized vehiclecomprising: a) a chassis supporting an engine and an endless track andhaving an operator platform; b) a framework mounted to said chassisincluding a drive sprocket coupled to said engine and a plurality ofidler wheels and wherein said track is trained around said sprocket andidler wheels; and c) wherein said endless track includes a longitudinalportion supporting a plurality of drive lugs that project from aninterior surface to engage said drive sprocket and a flexible pleatedportion, wherein a plurality of ground engaging lugs depend from anexternal surface of said track, wherein said pleated portion comprises aplurality of pleats that expand and contract to vary the contour of saidtrack when placed under pressure, and wherein said pleats are located tocontact said chassis and flex with operator movements to vary the trackcontour and steer said vehicle.
 23. A vehicle as set forth in claim 22wherein a bottom surface of said chassis contacting said pleated portionis contoured to induce pressure on said pleats.
 24. A vehicle as setforth in claim 22 wherein first and second pleated portions contain aplurality of pleats that respectively extend and rise at an acute anglefrom opposite lateral sides adjacent said drive lugs toward longitudinalperipheral edges of said track.
 25. A vehicle as set forth in claim 24wherein said pleats comprise compound raised V-shaped ridges thattransversely extend from an apex adjacent said drive lugs andprogressively rise and longitudinally flare as they extend to theperipheral edges of said track.
 26. A vehicle as set forth in claim 25wherein said pleats extend orthogonal to a longitudinal center axis ofsaid track and wherein said track includes an aperture at the apex ofeach pleat.
 27. A vehicle as set forth in claim 23 wherein the bottomsurface of said chassis contacting said pleated portion exhibits abeveled longitudinal surface that engages the pleats to flex the pleatswith operator movement.
 28. A vehicle as set forth in claim 27 includingfirst and second pleated portions containing pleats exhibiting compoundraised ridges that respectively extend and rise at an acute angle fromopposite lateral sides adjacent said drive lugs toward longitudinalperipheral edges of said track and wherein the bottom surface of saidchassis contacting the first sand second pleated portions respectivelyexhibits first and second beveled surfaces.
 29. A vehicle as set forthin claim 27 wherein said bottom surface includes a longitudinal recessintermediate the first and second beveled surfaces and wherein saiddrive lugs are restrained to pass along said recess.
 30. A vehicle asset forth in claim 29 wherein longitudinal sidewalls of said recessexhibit an arcuate shape.
 31. A vehicle as set forth in claim 28 whereinthe pleats of said first and second pleated portions orthogonally extendopposite each other along parallel axes transverse to a longitudinalcenter axis of said track.
 32. A vehicle as set forth in claim 22wherein said ground engaging lugs include recessed cavities.
 33. Avehicle as set forth in claim 32 wherein said track includes a pluralityof stiffener members mounted to transversely span said track, wherein astiffener member coaxially overlies each ground engaging lug, whereineach stiffener exhibits a bent portion overlying each recessed cavity,and wherein the bent portions of said stiffeners are defined at raisedinterior surfaces of said track.
 34. A vehicle as set forth in claim 22wherein said chassis supports a member mounted to move independent ofthe vehicle to contact and flex said pleats to vary the track contourand thereby provide steering control.
 35. A motorized vehiclecomprising: a) a chassis supporting an engine and an endless track andhaving an operator platform and wherein a bottom surface of said chassisincludes a contoured longitudinal pan; b) a framework mounted to saidchassis including a drive sprocket coupled to said engine and aplurality of idler wheels and wherein said track is trained around saidsprocket and idler wheels; and c) wherein said endless track includes alongitudinal center portion and first and second pleated portions,wherein said first and second pleated portions respectively comprise aplurality of ridged pleats that transversely extend and project from aground engaging track surface along opposed lateral sides of said centerportion toward longitudinal peripheral edges of said track, whereindrive lugs project from an interior surface of said center portion toengage said drive sprocket, wherein a plurality of ground engaging lugsdepend from the ground engaging track surface, and wherein said pleatsare mounted to contact said chassis pan with operator movements to flexand vary the track contour and thereby steer said vehicle.
 36. A vehicleas set forth in claim 35 wherein said pleats extend opposite each otheralong common parallel axes orthogonal to a longitudinal center axis ofsaid track.
 37. A vehicle as set forth in claim 35 wherein said pleatscomprise compound raised V-shaped ridges that transversely extend froman apex adjacent the drive lugs progressively rise at an acute angle asthey extend to the peripheral edges of said track.
 38. A vehicle as setforth in claim 35 wherein said pleats extend orthogonal to alongitudinal center axis of said track and wherein said track includesan aperture at the apex of each pleat.